As disclosed, e.g., in U.S. Pat. No. 4,179,580 (Cobb), it is known that supported and unsupported alkali metals are useful as catalysts in the coupling of ethylenically-unsaturated hydrocarbons with aromatic hydrocarbons having an active hydrogen on a saturated alpha-carbon. The supported alkali metals are more effective than the corresponding unsupported alkali metals in such reactions, but the use of a support has the drawbacks of involving filtration, handling, treatment, and disposal costs which it would be desirable to avoid.